Active-active replication reduces operational flexibility

Among the myriad data integrity and corruption risks associated with active-active replication, you also lose out on configurability and operational flexibility.

Reason 7 – Can’t add nodes easily

The often touted solution to use auto_increment_increment and auto_increment_offset fixes you to a given setup forever. You can set it up with a discrete two nodes, all primary keys on node1 being even, all on node2 being odd, or three nodes in a similar way.

But once you’ve set that up, adding a new node would require you to renumber every row in every table. A mountainous and painful undertaking.